HEREDITARY RETINAL DYSTROPHY

Hereditary Retinal Dystrophy — 280+ genes cause inherited blindness, and the first FDA-approved gene therapy (Luxturna) restores vision in RPE65-confirmed patients. Molecular diagnosis determines which of the growing list of gene therapies may apply.

Whole genome sequencing evaluates all 280+ retinal dystrophy genes simultaneously — including deep intronic variants, structural rearrangements, and the X-linked RPGR ORF15 region — providing the molecular diagnosis required for gene therapy eligibility.

RPE65
RPGR
ABCA4
USH2A

About this condition

Hereditary Retinal Dystrophy

Inherited retinal dystrophies (IRDs) are a genetically heterogeneous group of conditions causing progressive photoreceptor degeneration and visual loss, collectively affecting approximately 1 in 2,000-3,000 people worldwide — approximately 2 million affected individuals globally. Over 280 genes have been identified as causes of IRD, including retinitis pigmentosa (RP, the most common form), Leber congenital amaurosis (LCA), Stargardt disease, cone-rod dystrophy, choroideremia, achromatopsia, and others. Inheritance patterns include autosomal dominant, autosomal recessive, X-linked, mitochondrial, and digenic.

Clinical presentation varies by subtype but typically involves progressive loss of peripheral vision (rod-mediated, night blindness followed by tunnel vision in RP), central vision (cone-mediated, in Stargardt and cone dystrophies), or both. Many IRDs begin in childhood or young adulthood and progress to legal blindness by middle age. The specific gene and variant determine the rate of progression, the pattern of visual field loss, and — increasingly — eligibility for gene-specific therapies and clinical trials.

Voretigene neparvovec (Luxturna), an AAV-based gene therapy delivering functional RPE65, was FDA-approved in 2017 for RPE65-confirmed biallelic retinal dystrophy — the first FDA-approved gene therapy for any inherited disease. Luxturna restores navigational vision in patients with sufficient viable retinal cells. Since 2017, the gene therapy pipeline for IRDs has expanded dramatically: clinical trials are active for RPGR (X-linked RP), CNGA3/CNGB3 (achromatopsia), RS1 (X-linked retinoschisis), CHM (choroideremia), MERTK, RLBP1, and others. Molecular diagnosis identifying the specific causative gene is the essential prerequisite for all gene therapy eligibility — without it, patients cannot access these vision-saving treatments.

RPGR ORF15 — the most common cause of X-linked retinitis pigmentosa — contains a highly repetitive purine-rich region that standard short-read sequencing often fails to map correctly. WGS with appropriate bioinformatics resolves this technically challenging locus.

Gene locus: RPE65 (1p31.2), RPGR (Xp11.4), ABCA4 (1p22.1), USH2A (1q41), plus 280+ additional genes

280+ genes cause IRD. Panel testing covers 50-100. Deep intronic variants and structural rearrangements — invisible to panels — account for 10-15% of previously unsolved IRD cases. WGS evaluates the complete genetic landscape.

Gene therapy eligibility requires confirmed molecular diagnosis — and the treatment window closes as photoreceptors die

All IRD gene therapies require confirmed molecular diagnosis of the specific causative gene. Luxturna requires biallelic RPE65 variants. RPGR gene therapy trials require confirmed RPGR pathogenic variants. Beyond eligibility, most gene therapies require sufficient viable retinal cells — once photoreceptor degeneration is complete, gene therapy cannot restore vision. Every year of delayed molecular diagnosis is a year of continuing photoreceptor loss that narrows the gene therapy treatment window. WGS performed early in the disease course maximizes the time available for gene therapy intervention.

10-15% of IRD cases unsolved by panel testing are resolved by WGS — through deep intronic variants and structural rearrangements

Standard IRD gene panels test 50-100 known genes but evaluate only coding exons and flanking splice sites. Deep intronic variants that create cryptic exons (documented in ABCA4, CEP290, USH2A, and others), large structural rearrangements (inversions, complex deletions), and variants in newly identified IRD genes are missed. Multiple studies demonstrate that WGS resolves 10-15% of IRD cases that remained unsolved after panel testing, identifying the molecular diagnosis that opens the door to gene-specific clinical trials and emerging therapies.

Hereditary Retinal Dystrophy — 280+ genes cause inherited blindness, and the first FDA-approved gene therapy (Luxturna) restores vision in RPE65-confirmed patients. Molecular diagnosis determines which of the growing list of gene therapies may apply.

Hereditary Retinal Dystrophy

280+ genes cause IRD. Panel testing covers 50-100. Deep intronic variants and structural rearrangements — invisible to panels — account for 10-15% of previously unsolved IRD cases. WGS evaluates the complete genetic landscape.

Gene therapy eligibility requires confirmed molecular diagnosis — and the treatment window closes as photoreceptors die

10-15% of IRD cases unsolved by panel testing are resolved by WGS — through deep intronic variants and structural rearrangements

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